Fueling the Triathlon Machine

From May/June 2008 Oklahoma Runner & Triathlete
by Julie Pryer, RD/LD

Training for a triathlon or endurance event can be both grueling and taxing on the body. Many athletes train with their focus only on the workout itself. But, in order to get the most out of each workout, your body needs to be fueled appropriately. We’ve all heard the term performance nutrition, but what does it mean? This article aims to discuss how to fuel your body in a way that will decrease your risk of injury, improve recovery after workouts, and boost endurance and performance on a daily basis, that is, performance nutrition. Fueling your body with the right foods during workouts can result in performing your best during competition. Each athlete’s needs are dependent on the sport, training and ultimate goal. 

The most important things about performance nutrition are tailoring the food fuels you select to meet the needs of your training schedule, taking into account changes in training intensities and durations throughout the day, week, and season. It is essential to adjust your energy intake between a rest or recovery day and a heavy training day, because the difference in energy requirements can be significant. These modifications add up and are helpful in maintaining your proper race weight and energy balance.

Fueling with High Octane Foods
· Calibrating your Carbohydrate Needs:
· Moderate-duration and low-intensity training, you need 2.3 to 3.2 grams carbohydrate per pound of body weight each day.
· Moderate to heavy training, you need 3.2 to 5.5 grams carbohydrate per pound of body weight each day.
· Extreme training (4 to 6 hours), you need 4.5 to 5.5 grams carbohydrate per pound of body weight each day
· Perform with Protein: Endurance athletes should consume 0.55 to 0.77 grams of protein per pound of body weight. The secret to eating a balanced diet is to include adequate protein, but not too much. Excess protein displaces carbohydrates that are needed to fuel your muscles.
· Don’t Forget the Fat: Fat intake should range from 0.36 to 0.45 grams fat per pound body weight. Focus on the heart-healthy, unsaturated fats.
· Hydrate, hydrate, hydrate!

At every meal, include a combination of foods from at least 3 different food groups such as a bowl of whole grain cereal (grain), topped with a banana (fruit) and low-fat milk (dairy). At each snack, include at least 2 different food groups, for example Peanut butter (protein) and crackers (grain). By choosing from more food groups at each meal and snack, you are ensuring a more balanced diet higher in various vitamins and minerals. One key difference between a performance nutrition diet and a regular healthy diet, is it’s focus on carbohydrate-based meals that have only small amounts of fat (butter, fried foods, salad dressing) and a moderate serving of protein to ensure that higher carbohydrate demands can be met.

Understanding Energy Needs
So many athletes either overestimate or underestimate their energy needs during training. I am often presented with dilemmas from athletes trying to lose weight, who assume that with all of their exercise, fat should be falling off. This is not always the case since you need to be consuming more calories on higher volume training days, but less calories on recovery days and with lower duration and intensity exercise. This concept of overestimating needs is similar to putting more fuel in a full gas tank. It doesn’t work. While overeating can cause problems, underestimating your calorie needs can be detrimental to both endurance and performance during training and competition. Research has shown that athletes who are not fueling with adequate calories and carbohydrates have impaired endurance and stamina due to muscle and liver glycogen depletion. Depending on the training volume and intensity, most athletes require about 16-30 calories per pound of body weight.

Helpful Hint: An assessment with a dietitian to have your resting metabolic rate measured can help you get a more accurate gauge of your calorie needs.

Carbohydrates: The Fuel of Choice
Hands down, carbohydrates are the top choice to fuel the muscles. Our bodies store carbohydrate in our muscle and liver in the form of glycogen. These glycogen stores are limited, and can be depleted with moderate exercise lasting 2 to 3 hours, or during higher intensity exercise lasting 15 to 20 minutes. This is why consuming a diet higher in carbohydrates during training and competition is crucial for optimum performance.

Fun Fact: Both carbohydrate and fat contribute energy during exercise, but fat cannot supply energy fast enough during levels of higher intensity exercise.

Could an untrained person decide they want to compete in a triathlon or marathon one week before the race? For various reasons, this would not work out very well. An untrained individual has a glycogen storage capacity of approximately 13 grams/kg muscle. A trained muscle can store up to 32 grams of glycogen/kg of muscle and 35-40 grams if the person carbo-loaded before the event. In other words, a trained athlete has more than twice the storage capacity than an untrained person. So, an athlete must train appropriately in order to stimulate the muscle to store more glycogen.

The Best Carbohydrates
All forms of carbohydrate, either from refined sugars, or more complex carbohydrates will ultimately fuel your muscles and become stored as glycogen. But, why not get more bang for your buck, and choose a food that is high in carbohydrate AND is loaded with vitamins and minerals? In comparing a regular soft drink (AKA “empty calories”) to fruit juice that contains the same amount of carbohydrates along with vitamin C and potassium, the fruit juice wins (because it provides more than just carbohydrate). When thinking about overall health, its best to make choices that provide more nutrients such as fruits, vegetables, and whole grains as often as possible.

Pre-Exercise Fuel
Many athletes choose to skip pre-exercise meals, especially if they are training in the morning. Skimping on food in this situation poses a problem because the fasting that occurs overnight will deplete liver glycogen stores, especially if the last meal was earlier in the evening. Liver glycogen stores are responsible for maintaining normal blood glucose levels. It is common for an athlete who starts a workout with the combination of not eating and a low blood sugar to fatigue earlier than if they would have eaten something. A pre-exercise meal or snack does not provide immediate fuel to the muscles. For the athlete whose workout is longer than 1 hour, the meal does sustain blood glucose levels, and prevents hunger from occurring. If your training session is in the afternoon it is not always necessary to have a pre-exercise snack/meal. The key is to adequately fuel your body with breakfast, a morning snack, and lunch to fuel the afternoon workout.

The best pre-exercise fuel is one that is both high in carbohydrate and tolerated well by the athlete. For most athletes, consuming about 0.5 grams of carbohydrate per pound of body weight an hour before exercise or up to 2 grams of carbohydrate per pound, 4 hours before training is sufficient. The closer to exercise that the meal is consumed; the lower the calorie and carbohydrate content should be in order to prevent stomach problems.

Choose pre-exercise meals/snacks that are high carbohydrate, low-fat, moderate in protein and tested during training.

Fuel During Exercise
Fueling during exercise or competition lasting more than 1 hour improves endurance and performance by providing a constant flow of glucose when glycogen stores are more depleted. A goal of 30 to 60 grams of carbohydrate per hour from foods in either solid or liquid form is acceptable. Both liquid and solid sources of carbohydrate have their advantages, however, it is important to find the source that your system tolerates best. Liquids tend to encourage hydrating, while solids (gels, energy bars) are portable and provide a little more variety. Drinking 24 fluid ounces of a sports drink containing 6% to 8% carbohydrate provides 42 to 57 grams of carbohydrate per hour while helping maintain hydration. Some studies have shown that beverages that are more than 9% carbohydrate slow absorption rate, thereby promoting cramps, nausea, and diarrhea. While beverages that are less than 5% carbohydrate will supply fluid, it will not provide adequate carbohydrate. Solid forms of carbohydrate could include 1/3 cup of raisins (30 grams of carbohydrate), a sports bar (45 grams carbohydrate) or 2 gel packs (about 25 grams carbohydrate each). Make sure you drink plenty of fluids with the gels to avoid stomach distress.

Put together a list of high carbohydrate foods that you have tested during training. It is important to train your stomach and your body to consume these foods in the same way you are training your muscles to work. So many athletes hesitate to try foods and/or liquids during training, fearing it will negatively affect the training session, but it’s better to find out now than during the competition.
FUN FACT: Research has shown that when exercising for longer than 90 minutes, consuming a pre-exercise meal or snack AND fueling during exercise is more effective than only fueling once.

Recovery Fuel
After intense exercise, the best time to start refueling for the next training session is immediately, or as soon as it’s tolerable (within 2 hours). At this time the muscles are like sponges, taking up carbohydrates to replenish glycogen stores. Within the first hour after an intense training session lasting over 1 hour, 0.5 to 0.75 grams of carbohydrate will begin the recovery process. After the initial recovery intake, aim for 0.5 to 0.75 grams of carbohydrate every 2 hours, for up to 6 hours. While choosing higher glycemic index foods during recovery may be beneficial, it is most important to consume the recommended amount of carbohydrate for adequate glycogen repletion. Although including protein in recovery meals/snacks has not been shown to increase muscle glycogen uptake, it may stimulate muscle protein synthesis. One of the best recovery choices is low fat chocolate milk, which provides carbohydrate and protein.

Foods that contain approximately 30 grams of carbohydrate per serving:
Whole wheat bread (2 slices)
Pasta (1 cup, cooked)
Baked potato (medium)
Oatmeal (1 cup, cooked)
Cold cereal (3/4 to 1 cup)
Beans (3/4 cup, cooked) – are you sure it’s not 1 cup?
Gatorade (16 oz)
Granola bar
Jam or Honey (2T)
Chocolate Milk (1 cup)
Banana (1 large)
Grapes (1 cup)
Raisins (1/3 cup)
Orange Juice (8 oz)